This invention relates to wood preservative and waterproofing compositions containing an amine oxide and an isothiazolone.
Isothiazolones are known to be effective as wood preservatives. Many isothiazolones, however, have low water solubility. As a result, solutions containing them often have two or more phases.
U.S. Pat. No. 5,536,305 provides compositions comprising (a) a water insoluble wood preservative compound, such as an isothiazolone; (b) a surfactant system consisting of one or more surfactants selected front the group consisting of sulfonated anionics, sulfonated anionics, sulfosuccinated anionics, quaternary ammonium cationics, and amphoterics; and (c) optionally non-polar organic solvents.
There is a continuing need for improved isothiazolone wood preservatives and waterproofing compositions which have only one phase.
Applicants have discovered that amine oxides enhance the performance of isothiazolones as wood preservatives and provide waterproofing properties. Amine oxides also aide in solubilizing isothiazolones into aqueous solutions. The present invention provides a composition comprising an amine oxide and an isothiazolone.
Another embodiment of the present invention is a method for preserving and/or waterproofing a wood substrate by contacting the wood substrate with the composition.
Yet another embodiment is an article comprising a wood substrate and the composition of the present invention.
The present invention provides a composition comprising an amine oxide and an isothiazolone. The amine oxide enhances penetration of the isothiazolone into wood substrates and improves leach resistance. Furthermore, the amine oxides aide in solubilizing the isothiazolone in water. As a result, aqueous solutions containing isothiazolones and amine oxides may be formed which have only one phase. The compositions of the present invention also have low volatility.
The amine oxide may be a trialkylamine oxide; an N-alkylcyclicamine oxide; a dialkylpiperazine di-N-oxide; an alkyldi(poly(oxyalkylene))amine oxide; a dialkylbenzylamine oxide; a fatty acylamidopropyldimethylamine oxide; a diamine oxide; a triamine oxide; and any combination of any of the foregoing. Preferably, the amine oxide includes at least one C8-C18 alkyl moiety.
Preferred trialkylamine oxides have the formula R1R2R3Nxe2x86x92O, where R1 is a linear, branched, cyclic or any combination thereof C8 to C40 saturated or unsaturated group; and R2 and R3 independently are linear, branched, or any combination thereof C1 to C40 saturated or unsaturated groups. R1, R2, and R3 independently may be alkyl, alkenyl, or alkynyl groups. More preferably, R1 is a linear, branched, cyclic or any combination thereof C8 to C22 saturated or unsaturated group, such as coco, hydrogenated tallow, soya, decyl, and hexadecyl; and R2 and R3 independently are linear, branched, or any combination thereof C1 to C22 saturated or unsaturated groups, such as coco, hydrogenated tallow, soya, decyl, and hexadecyl.
A preferred trialkylamine oxide is a dialkylmethylamine oxide having the formula R1R2CH3Nxe2x86x92O, where R1 and R2 are defined as above. Another preferred trialkylamine oxide is an alkyldimethylamine oxide having the formula R1(CH3)2Nxe2x86x92O, where R1 is defined as above. More preferred alkyldimethylamine oxides have the formula R19(CH3)2Nxe2x86x92O, where R19 is a linear or branched C8-C18 alkyl or alkenyl. Preferably, R19 is a linear or branched C8-C16 alkyl. Alkyldimetlylamine oxides are non-toxic and non-mutagenic surfactants. Suitable alkyldimethylamine oxides include, but are not limited to, a C10 alkyldimethylamine oxide, a C10-C14 alkyldimethylamine oxide, a C12-C16 alkyldimethylamine oxide, a C16-C18 alkyldimethylamine oxide, and any combination of any of the foregoing.
Preferred N-alkylcyclicamines oxide have the formula R4R5R6Nxe2x86x92O where R4 is defined as R1 above and R5 and R6 are linked to form a cyclic group. The cyclic group typically contains from about 4 to about 10 carbon atoms and may optionally contain oxygen, sulfur, nitrogen, or any combination of any of the foregoing. More preferred alkylcyclicamine oxides include, but are not limited to, an alkylmorpholine N-oxide, a dialkylpiperazine di-N-oxide, and any combination of any of the foregoing.
Preferred alkylmorpholine N-oxides have the formula 
where R7 is defined as R1 above.
Preferred dialkylpiperazine di-N-oxides have the formula 
where R8 is defined as R1 above and R9 is defined as R2 above.
Preferred alkyldi(poly(oxyalkylene))amine oxides have the formula 
where R10 is defined as R1 above; R11 and R12 independently are H or CH3; and m and n independently are integers from about 1 to about 10.
Preferred dialkylbenzylamine oxides have the formula R13R14R15Nxe2x86x92O, where R13 is defined as R1 above; R14 is defined as R2 above; and R15 is benzyl. More preferred dialkylbenzylamine oxides include, but are not limited to, alkylbenzylmethylamine oxides having the formula R13R15CH3Nxe2x86x92O where R13 and R15 are defined as above.
Preferred fatty acylamidopropyldimethylamine oxides have the formula 
where R16 is defined as R1 above.
Preferred diamine oxides have the formula 
where R17 is defined as R1 above; and m is an integer from about 1 to about 10.
Preferred triamine oxides have the formula 
where R18 is defined as R1 above; and m and n independently are integers from about 1 to about 10.
Long chain (C16 or greater) amine oxides, such as hexadecylamine oxides and hydrogenated tallow amine oxides, are particularly preferable for imparting waterproofing properties to the composition. Short chain (C14 and shorter) amine oxides aide in solubilizing the isothiazolone and long chain amine oxides.
A blend of long chain and short chain amine oxides is also contemplated in one embodiment of the present invention. For example, the composition may contain a mixture of C16-C18 long chain amine oxides to impart waterproofing properties and C10-C14 short chain amine oxides to solubilize the long chain amine oxides. The long chain amine oxides may be blended with the short chain amine oxides in a ratio of about from about 1:10 to 10:1 in order to yield a stable preservative solution. More preferably, the ratio ranges from about 1:1 to about 2:1.
Suitable isothiazolones include, but are not limited to, benzisothiazolone (such as 1,2-benzisotiiazolone), 4,5-dichloro-2-octyl-3(2H)-isothiazolone, 2-octyl-3(2H)-isothiazolone, 4,5-trimethylene-3(2H)-isothiazolone, and any combination of the foregoing. Preferred isothiazolones include, but are not limited to, 3-isothiazolones, such as those disclosed in U.S. Pat. Nos. 4,105,431 and 3,761,488, both of which are wherein incorporated by reference. The composition may include a solvent, such as water and water miscible solvents, including, but not limited to, alcohols, such as ethanol; glycols; esters; ethers; polyethers; and any combination of any of the foregoing. Preferably, the composition does not include xylene and more preferably does not include a solvent other than water.
The weight ratio of amine oxide to isothiazolone broadly ranges from about 100:1 to about 1:1 and preferably from about 50:1 to 5:1.
According to one embodiment of the invention, the composition in concentrated form contains broadly from about 5 to about 100%, preferably from about 10 to about 50%, and more preferably from about 20 to about 35% by weight of combined amine oxide and isothiazolone based upon 100% weight of total composition.
Use dilutions of the composition typically comprise a biocidally effective amount of isothiazolone and a preservative enhancing and/or waterproofing effective amount of the amine oxide. Use dilutions preferably comprise from about 0.1 to about 5.0% by weight of amine oxide and from about 0.005 to about 0.5% by weight of isothiazolone based upon 100% weight of total composition.
Other adjuvants may be included in the composition as known to one of ordinary skill in the art. Other biocides, fungicides and insecticides may be include in the composition. Any organic insecticide or fungicide that can be solubilized by an aqueous amine oxide solution is suitable for use in the present composition. Suitable insecticides include, but are not limited to, chloropyrifos, folpet, captafol, captan, pyretiroids, and any combination of any of the foregoing. Suitable fungicides include, but are not limited to, iodopropargyl butylcarbamate, tributyltin oxide, 2-(thiocyanomethylthio)benzothiazole, iodo-sulfones, azoles, isothiazalones, and any combination of any of the foregoing.
Another embodiment of the present invention is a method for preserving and/or waterproofing a wood substrate by contacting the composition of the present invention with the wood substrate. The composition may be applied to the wood substrate by any method known to one of ordinary skill in the art including, but not limited to, brushing, dipping, soaking, vacuum impregnation, and pressure treatment using various cycles.
The composition of the present invention may be prepared by mixing the isothiazolone, amine oxide, solvents, and adjuvants. The mixture may be heated and/or stirred to expedite mixing.